In recent years, damage to the environmental has become a problem, and clean energy that does not result in the production of harmful waste is required. Exhaustion of fossil fuels has also become a problem, and a new energy source is in demand. Meanwhile, in the electronics field, the amount of information that needs to be processed continues to dramatically increase, leading to the increase in electric power consumption of the electronic equipment.
Thus, hydrogen, which is contained in water that is inexhaustible on Earth, has a large chemical energy, and does not discharge harmful substances, has attracted attention as an energy source. A fuel cell, which directly produces electric energy, can extract a large amount of electric power with the highly efficient use of hydrogen, and therefore, can be used in automobiles and portable electronic devices, such as notebook computers, mobile phones and digital camcorders, is being advanced.
A so-called fuel cell, which extracts electrical energy from hydrogen, has a hydrogen electrode to which hydrogen is supplied and an oxidation electrode to which oxygen is supplied, separates hydrogen atoms into electrons and protons by a catalytic reaction in the hydrogen electrode. The protons pass through an electrolyte membrane and then reach the oxidation electrode and react with oxygen by a catalytic reaction, whereby water is generated. Along with the water, a flow of electrons, namely electric power, is also generated.
Unlike the conventional batteries, fuel cells do no need an electric charge, and it is possible to generate electric power immediately by only replenishing it with fuel after the fuel is used up, which is convenient for a long-term use of a device.
A fuel cell system that supplies fuel into the fuel cell system from a fuel cartridge is described, for example, in Japanese Patent Application Laid-open No. 2002-158022.